Cutinases are lipolytic enzymes capable of hydrolyzing the substrate cutin. Cutinases are known from various fungi (P. E. Kolattukudy in “Lipases”, Ed. B. Borgström and H. L. Brockman, Elsevier 1984, 471-504). The amino acid sequence and the crystal structure of a cutinase of Fusarium solani pisi have been described (S. Longhi et al., Journal of Molecular Biology, 268 (4), 779-799 (1997)). The amino acid sequence of a cutinase from Humicola insolens has also been published (U.S. Pat. No. 5,827,719).
A number of variants of the cutinase of Fusarium solani pisi have been published: WO 94/14963; WO 94/14964; WO 00/05389; Appl. Environm. Microbiol. 64, 2794-2799, 1998; Proteins: Structure, Function and Genetics 26, 442-458, 1996; J. of Computational Chemistry 17, 1783-1803, 1996; Protein Engineering 6, 157-165, 1993; Proteins: Structure, Function, and Genetics 33, 253-264, 1998; J. of Biotechnology 66, 11-26, 1998; Biochemistry 35, 398-410, 1996; Chemistry and Physics of Lipids 97, 181-191, 1999; Proteins: Structure, Function, and Genetics 31, 320-333, 1998; Biochimica et Biophysica Acta 1441, 185-196, 1999; Appl. Environm. Microbiol. 64, 316-324, 1998; BioTechniques 27, 1102-1108, 1999.
Fungal cutinases may be used in the enzymatic hydrolysis of cyclic oligomers of poly(ethylene terephthalate), e.g. in the finishing of yarn or fabric from poly(ethylene terephthalate) fibers (WO 97/27237). It is desirable to improve the thermostability of known fungal cutinases to allow a higher process temperature.